Car dumper dust control system

ABSTRACT

A method and apparatus that reduce release of dust generated during rotary dumping of rail cars in a dumping facility. The method includes removing dust laden air from a space bounded by a backside airflow diverter, a rotational frame, a first baffle and a second baffle while the rotational frame is rotating with a rail car by drawing the dust laden air through a secondary air intake that passes through the backside airflow diverter into a backside hood. A dust control apparatus includes a diverter, overlying a backside hood having a concave curved upper surface; and at least one secondary air intake positioned to pass through the diverter being located approximately where pressure in the backside hood remains neutral or negative relative to a pressure even there is a transient increase in air pressure in a lower portion of the backside hood.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/249,584,filed Jan. 16, 2019, entitled “Car Dumper Dust Control System,” which isa continuation of application Ser. No. 15/414,299, filed Jan. 24, 2017,entitled “Car Dumper Dust Control System”, now U.S. Pat. No. 10,189,657,issued Jan. 29, 2019, which is a continuation of application Ser. No.14/800,851 entitled “Car Dumper Dust Control System”, filed Jul. 16,2015, now U.S. Pat. No. 9,604,800, issued Mar. 28, 2017, which is acontinuation of application Ser. No. 14/045,401 entitled “Car DumperDust Control System”, filed Oct. 3, 2013, now U.S. Pat. No. 9,108,809,issued Aug. 15, 2015, which is a continuation of application Ser. No.13/623,423 entitled “Car Dumper Dust Control System”, filed Sep. 20,2012, now U.S. Pat. No. 8,568,077, issued Oct. 29, 2013, which is acontinuation of application Ser. No. 13/101,587, entitled “Car DumperDust Control System”, filed May 5, 2011, now U.S. Pat. No. 8,292,566issued Oct. 23, 2012, which is a continuation of application Ser. No.12/332,826 entitled “Car Dumper Dust Control System”, filed Dec. 11,2008, now U.S. Pat. No. 7,959,398 issued Jun. 14, 2011, the entirecontents of all of the above applications are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to rotary-dumping of material from railcars, and more particularly, to a method and apparatus for controllingenvironmental contamination produced by rotary-dumping material fromrail cars.

BACKGROUND

Rail cars have been used for many years to efficiently haul largequantities of bulk materials over land. Items commonly shipped includegrain, iron ore and coal. Shipping such items via rail car is veryefficient due to the ability to transport extremely large loads of thesematerials in one shipment. For example, one single rail car may hold upto 110 tons of coal and an entire train made up of such cars may be over130 cars in length, extending 6000 feet in total length.

Once at the destination, it is necessary to unload the cargo. For bulkmaterial such as grain, ore, or coal, bottom-dumping and rotary-dumpingare commonly used. Bottom-dumping involves staging a particular car overa receiving pit and opening hatches located in the bottom of the car.The cargo exits the car though the bottom hatches or doors and proceedsinto the pit below. U.S. Pat. No. 5,302,071, assigned to SvedalaIndustries, Inc., discloses one example of a bottom-dumping rail car.

Bottom-dumping requires the use of rail cars that are specificallydesigned for bottom-dumping. This is due to the need to direct the carcontents to a centrally located chute on the bottom of the car. Thesides of the car must be at least partially sloped to urge the contentstowards the chute, or else there would be a partial retention of thematerial being carried. This configuration decreases the ratio of thecar's size vs. cargo capacity. Additionally, the bottom-dump configuredrail cars are not easily interchangeable with standard cars at adumpsite because the dump apparatus for standard cars must be uniquelyconfigured to accommodate bottom-dump cars. The bottom-dump rail carsare also environmentally disadvantageous, as will be described morefully below.

Rotary-dumping is the other commonly used method of unloading a railcar. In rotary-dumping, a standard rectangular rail car is staged orindexed in a rotary-dump apparatus. The apparatus then rotatesapproximately one-half turn, thereby dumping the contents of the carinto a receiving pit. Typically, the cars of the train remain connectedduring the dumping process through the use of rotary couplings betweeneach car. Such couplings permit the cars to be rotated while stillconnected though an axis center at the coupling. U.S. Pat. Nos.4,479,749 and 4,609,321, both assigned to Dravo Corporation, discloseconventional rotary-dump apparatuses. In some applications, such as thedumping of coal at major power plants, cars may be rotated and emptiedat the rate of one car every four minutes.

Environmental pollution is an important concern to the design of amaterial dumping facility. When the car's load is dumped, a largequantity of material exits the car in a very short time. The turbulencegenerated by the quick unloading causes fine dust particles to billow upfrom the receiving pit and pollute the air surrounding the dumpfacility. The resulting dust, such as from grain or coal, is veryexplosive when in sufficient density. It is also an environmentalpollutant. Therefore, there is a need to provide an apparatus and methodfor minimizing the polluting effect of dust.

Bottom-dump apparatuses have two critical drawbacks. First, they requirespecial cars equipped with the bottom chutes as discussed previously.Second, the dust cloud produced by bottom-dumping is recognized by thoseskilled in the art to be larger, more aggressive and less controllablethan the cloud produced by the rotary-dump method.

Rotary-dump systems control the dust cloud by using fans with largemotors to exhaust the dust-filled air surrounding the car thoughconduits and into filtering devices. This process requires a very highflow of air and correspondingly very large motors to drive such highcapacity system. These motors are commonly several hundred horsepower.Multiple motors of this size may be required at any given installation.

The dust cloud is typically large enough and aggressive enough tooverpower any reasonably sized removal system. Therefore, the airflowaround the car and in the pit is controllably designed to keep the dustcloud suppressed long enough to allow the dust collection system to suckthe dust from the surrounding area. The better the airflow is managed,the less horsepower is needed to drive the system. This results ingreatly improved efficiency.

Prior art patents disclose a method of enclosing a rail car within afixed enclosure. This design has several drawbacks. First, it restrictsthe operator's ability to observe the load as it is being dumped toensure that the system does not malfunction and that no impurities orforeign objects are introduced into the pit. Next, the fixed enclosurerequires multiple large motors to drive the plurality of air handlingunits. The filtering portions of the air handling units are within thedumping facility, which makes cleaning and maintenance more difficult.Finally the efficiency of the system is low due to the large motorsrequired to produce sufficient air removal capacity because the controlof the airflow around the car does not have good dust cloud retentiontime.

There are two different types of rotary car dumpers in common use. Thoseskilled in the art refer to the two types of dumpers as rings outdumpers and rings in dumpers. The rings referred to are the structuralends of a car dumper which support the entire car dumper barrel and therailcar itself. Depending upon the design of a rotary car dumper it mayhave the rings located at the far ends of the dumper barrel, a rings outdesign, or it may have the rings located approximately one quarter ofthe length of the barrel in from the ends, the rings in design.

When a railroad car is dumped more air is displaced by the rush ofproduct exiting the railcar than can be evacuated by a blower system ina period of time during the dump. Thus, there is a tendency for themoving dust laden air to escape from the car dumper pit by any exit paththat may be available.

Prior art car dumper dust control systems have made great improvementsin dust control. However, dust still escapes from car dumpers insufficient quantity to create significant air pollution and depositionof dust onto horizontal surfaces in the vicinity of car dumpers.

Often, attempts have been made to control the remaining escaping dust bywet suppression techniques. That is water is sprayed into the area todampen the dust particles. This causes them to fall to the ground orother horizontal surface. Wet suppression is generally effective inremoving dust from the air. Unfortunately, wet dust adheres toeverything it comes into contact with in the area and is difficult toclean up.

Prior dust control systems are described in U.S. Pat. Nos. 6,960,054 and7,322,785 which are assigned to the assignee of the present application.

Therefore, there is a continuing need to provide a rotary-dumper dustcollection apparatus and system that overcomes the drawbacks of theprior art.

SUMMARY

The present invention addresses the disadvantages in the prior art andthe need to provide an environmentally friendly and efficient way tounload rail cars by providing a method and apparatus for controllingdust generated by the rotary dumping of rail cars. One or more flexiblebaffles are provided to the back-side of a rotary dump frame to seal aportion of the material receiving pit during at least a portion of therotary motion. The dust cloud generated by this dumping is retained inthe pit for an increased time due to tumbling of the cloud induced bythe baffles and other features of the facility. A plurality of intakeducts removes the dust cloud from the pit for transfer to a remotefiltering facility.

The present invention provides for additional air intakes be placed at alocation where they can assist in extracting dust laden air from betweenthe baffles.

Car dumpers that have been adapted for dust control still release somedust into the environment. As will be discussed below, there is atendency for dust to be trapped between the baffles which hang down andseal between the car dumper carriage and the ski jump or backsidediverter during at least part of the dumping process. Dust trappedbetween the baffles tends to be released in a puff of dust when theleading baffle clears the upper outer edge of the ski jump and is nolonger in contact with ski jump.

A rotary car dumping facility with relation to the present inventiongenerally includes an interior and an exterior. Within the interior islocated a material receiving pit. The pit has a dump side and a backside. A rotational frame is located at least partially in the pit and isadapted to receive a loaded rail car and to dump the load from the railcar during rotational motion of the rotational frame and the rail car.The rail car starts in an upright position where the entire load is inthe rail car and is rotated by the rotational frame to a dumpingposition where the load exits the rail car. Inside the pit is located abackside airflow diverter, also known as a ski jump. The backsideairflow diverter is located adjacent the backside of the pit andincludes a curved upper surface which, because of its shape leads tobeing referred to as the ski jump.

The backside hood for removing contaminated air from the backside of thepit is also located on the backside of the pit generally beneath thebackside diverter. The rotational frame supports one or more bafflesthat hang downward from the rotational frame and make contact with theupper surface of the backside airflow diverter during at least a portionof the rotational motion. The present invention is particularly usefulin the context of a car dumper that has at least two baffles disposed onthe rotational frame.

The baffles located on the rotational frame are separated by somedistance so that as one baffle leaves the top of the backside airflowdiverter, a second baffle is still in contact with the top of thebackside airflow diverter and a third baffle may be making contact withthe lower edge of the backside airflow diverter. Thus, there is a spacelocated between each pair of the baffles. A first space located betweenthe first and second baffle and a second space located between thesecond and third baffle.

Dust laden air often occupies the spaces between the first and secondbaffle and the second and third baffle. The present invention allows forthe removable of the dust laden air from the space between the bafflesto a filtering facility where dust and particulate matter in the dustladen air can be removed before the air is released into the surroundingenvironment.

For the purposes of this discussion, a car dumping facility with threecurtain baffles secured to the rotational dumping frame will bediscussed. However, this should not be considered to be limiting. Alarger or smaller number of curtain baffles may be utilized inaccordance with the present invention.

As the rotational frame begins its rotation, from an upright position,none of the curtain baffles are in contact with the upper surface of thebackside airflow diverter. As the rotation continues, the first curtainbaffle makes contact with the backside airflow diverter and forms a sealbetween the rotational frame and the backside airflow diverter. Duringthis time period, dust laden air from the dumping process can enter thespace behind the first baffle. As the rotational frame continues itsrotation, the second baffle makes contact with the lower edge of thebackside airflow diverter. When this contact is made, dust laden airthat is in the space behind the first baffle but in front of the secondbaffle, is trapped in the space bounded by the rotational frame, thefirst baffle, the second baffle and the upper surface of the backsideairflow diverter. As rotation continues, the first baffle clears the topedge of the backside airflow diverter, at this time there tends to be apuff of dust laden air that escapes from the space between the first andsecond baffle. In the prior art, this dust laden air is released intothe environment and contributes to environmental pollution in the areasurrounding a car dumper. As rotation of the car dumper continues, thesecond baffle remains in contact with the upper surface of the backsideairflow diverter and the third baffle makes contact with the lower edgeof the backside airflow diverter and continues up to the top of thebackside airflow diverter. At this time dust laden air can be capturedin the space bounded by the second baffle, the third baffle, therotational frame and the upper surface of the backside airflow diverter.As rotation continues to the final dumping position, the second baffleclears the upper edge of the backside airflow diverter and a second puffof dust laden air may be released into the environment surrounding thecar dumping facility. After the car is completely dumped, the rotationalframe reverses its rotational direction and returns to an uprightposition. The present invention removes dust laden air from the spacebetween the first and second baffle and the space between the second andthird baffle prior to that dust laden air being released into theambient environment as a puff of dust laden air.

The present invention includes at least one additional air intake thatpasses through upper surface of the backside airflow diverter at alocation so that dust laden air can be drawn into the backside hood andremoved from the space between the first and second baffle and the spacebetween the second and third baffle before these spaces are opened tothe ambient atmosphere and allow release of the dust laden air into thesurrounding environment.

The additional air intakes in accordance with the present invention arelocated at a position relative to the backside hood where the backsidehood narrows as it approached attached ductwork, thus creating a higherspeed flow of air to the filter system that is utilized with the cardumper of the present invention. The additional air intake is alsolocated so that the edge of the first baffle passes the additional airintake after the edge of the second baffle has made contact with thelower edge of the upper surface of the backside airflow diverter. Thisprevents the additional air intakes from drawing additional dust ladenair from the pit into the space between the baffles.

Thus, dust laden air is withdrawn from the space between the firstbaffle and the second baffle while the rotational frame is rotating. Inaccordance with the present invention, the location of the additionalair intake is also such that the second baffle passes the location ofthe additional air intake shortly after the third baffle makes contactwith the lower edge of the backside airflow diverter.

In accordance with the present invention, the additional air intake issized to allow for essentially complete evacuation of dust laden airfrom between the first baffle and the second baffle or the space betweenthe second baffle and the third baffle prior to the leading bafflebreaking contact with the upper edge of backside airflow diverter.

Additional air intakes in accordance with an example embodiment of thepresent invention, may take the form of generally horizontally orientedslits passing through the upper surface of the backside airflow diverterand into the backside hood. The additional air intakes are locatedaligned with at least one of the air intake ducts that are positionedbeneath the backside airflow diverter. The additional air intakes mayalso be formed in other shapes including circular or square.

In some example embodiments of the present invention it is beneficial ifthe edges of the additional air intake are chamfered or rounded.Chamfering or rounding may minimize wear on the edges of the baffles asthey pass over the additional air intakes.

During operation of a car dumper prior to dumping of a rail car whilethe exhaust fans are operating, pressure inside of the backside hood isnegative relative to the inside of the pit because of the operation ofthe exhaust fans. When a railway car is being dumped, the solid granularmaterial being dumped from the rail car rushes downward into the pit andcarries along with it a great deal of air. This down rushing airincreases pressure inside the car dumper pit for a period of time andbriefly causes there to be positive pressure within at least the lowerportion of the interior of the backside hood. This positive pressurereaches some distance up the backside hood toward the air intake ductwork. As the backside hood narrows and transitions to the ductwork thevelocity of air flow increases as a result of the fans withdrawing airthus transitioning from positive pressure to negative pressure.

Described another way, the pit is subject to spike increases in pressureinitiated by the load exiting the rail car and entering the pit. Thespike increases in pressure travel into the backside hood an attenuatingdistance from a primary hood intake before being attenuated. Theattenuating distance is that distance from the primary hood intake atwhich the pressure within the backside hood is less than or equal to thepressure in the interbaffle space.

In an example embodiment of the invention at least one secondary airintake is positioned to pass through the upper surface of the backsidediverter into the backside hood at a location at least the attenuatingdistance from the primary intake.

In accordance with an example embodiment of the present invention, theadditional air intakes are positioned in a zone of the backside hoodwhere there is always neutral or negative pressure relative to theinside of the pit. This positioning overcomes a tendency for dust ladenair passing into the backside exhaust hood under pressure from the pitto puff out of the additional air intakes into the space between thebaffles and then into the environment. Thus, in accordance with thepresent invention, the additional air intakes may be positioned at alocation toward the upper end of the backside hood where pressure in thebackside hood remains neutral or negative even when downwardly rushingmaterial dumped from the rail car into the pit and air that accompaniesit transiently increase pressure in the lower portion of the backsidehood. In an example embodiment the location of the additional airintakes is near the location of the transition from the top end of thebackside hood to the exhaust duct that draws air from the backside hood.

In another example embodiment, the invention includes a method ofreducing release of dust generated during rotary dumping of rail cars ina dumping facility. The facility includes a material receiving pit thathas a dumpside and a backside. A rotational frame is disposed at leastpartially in the pit and is configured to dump a load from a rail carduring rotational motion of the rotational frame between an uprightposition wherein the load is in the rail car and a dumping positionwherein the load can clear the rail car supports baffles. A backsideairflow diverter is within the pit adjacent the back side of the pit. Abackside hood is located generally beneath the backside diverter. Thebaffles each present a leading edge that is configured to contact thebackside airflow diverter during at least a portion of the rotationalmotion. The pit is subject to spike increases in pressure initiated bythe load clearing the rail car and entering the pit. The spike increasesin pressure travel into the backside hood an attenuating distance from aprimary hood intake before being attenuated. The attenuating distance isthat distance from the primary hood intake at which the pressure withinthe backside hood is less than or equal to the pressure in theinterbaffle space. The method includes locating at least one secondaryair intake positioned to pass through the upper surface of the backsidediverter into the backside hood at a location at least the attenuatingdistance from the primary hood intake.

The above summary is not intended to describe each illustratedembodiment or every implementation of the subject matter hereof. Thefigures and the detailed description that follow more particularlyexemplify various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter hereof may be more completely understood in considerationof the following detailed description of various embodiments inconnection with the accompanying figures, in which:

FIG. 1 is a fragmentary end elevational view of a rail car dumper inaccordance with an embodiment of the invention;

FIG. 2 is a top plan view of the car dumper of FIG. 1 taken alongsection line 2-2;

FIG. 3 is a detailed view of the area encircled at 3 in FIG. 2;

FIG. 4 is a detailed view of the area encircled at 4 in FIG. 1;

FIG. 5 is an end view of the car dumper of FIG. 1 with a dumping framebeginning to rotate;

FIG. 5A is a detailed view of area 5A in FIG. 5;

FIG. 6 is a detailed view of area 6 in FIGS. 5 and 5A;

FIG. 7 is an end view of the car dumper of FIG. 1 with the dumping frameabout midway in its rotation;

FIG. 7A is a detailed view of area 7A in FIG. 7;

FIG. 8 is an end view of the car dumper of FIG. 1 with the dumping framenear the end of its rotation; and

FIG. 8A is a detailed view of area 8A in FIG. 8.

While various embodiments are amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the claimedinventions to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the subject matter as defined bythe claims.

DETAILED DESCRIPTION OF THE DRAWINGS

Car dumper facility 10 of the present invention generally includes upperportion 12 and lower portion 14. Rotational frame 16 is disposed withincar dumper facility 10, generally overlapping upper portion 12 and lowerportion 14.

Car dumper facility 10 also includes dust removal apparatus 18. Curvedarrows in FIGS. 5, 5A, 6, 7, 7A, 8 and 8A demonstrate the generaldirection of airflow in accordance with the invention.

Lower portion 14, in an example embodiment, generally includes pit 20,grizzly 22, backside diverter 24, dumpside diverter 26 and dumpsidebaffle 28.

Pit 20 is covered by grizzly 22. Grizzly 22 is a grate having aperturesof a size appropriate to receive the coal or other granular materialdumped while not large enough to pass foreign matter that they be mixedwith the dumped material. Backside diverter 24 is located in pit 20 onthe backside and has a generally curved upper surface. Backside diverter24 is also sometimes known as the ski jump because of its shape.Dumpside diverter 26 is located on the dumpside of pit 20 and isgenerally sloped toward grizzly 22 and extends upwardly away toward theexterior of pit 20. Dumpside baffle 28 is located on the dumpside of pit20 and is generally stationary and secured to structure in or above pit20.

Rotational frame 16 is rotationally disposed above pit 20 and is adaptedto support rail car 30. Rotational frame 16 generally includes rail carsupport 32 positioned so that rotational axis 34 coincides withrotational coupler (not shown) of rail car 30. Rotational frame 16generally includes counter weight 36 and baffle support 38. Bafflesupport 38, in an example embodiment, supports first baffle 40, secondbaffle 42 and third baffle 44. First baffle 40, second baffle 42 andthird baffle 44 are flexible and/or are hingedly supported by bafflesupport 38. First baffle 40, second baffle 42 and third baffle 44 may bepartially or completely formed of flexible material. For example, firstbaffle 40, second baffle 42 and third baffle 44 may be formed of a heavyweight flexible rubber or polymer material. Further, they may be formedof a ridged or semi-ridged structural material and have a flexible seal(not shown) at the lowest edge thereof.

Dust removal apparatus 18 generally includes dumpside hood 46, dump sideductwork 48, backside hood 50 and backside duct work 52. Dumpside hood46 is generally located on the dumpside of car dumper facility 10.Dumpside hood 46, in an example embodiment, is positioned in upperportion 12 of car dumper facility 10. Dumpside hood 46 is in fluidcommunication with dump side ductwork 48. Dumpside ductwork 48 leads toan exhaust fan (not shown) which is coupled to a filtering facility (notshown) located in or near car dumper facility 10. Dumpside hood 46includes dumpside intake 54. Dumpside intake 54 is located near andgenerally above dumpside diverter 26. Dumpside baffle 28 is located, inan example embodiment, adjacent to dumpside intake 54.

In an example embodiment, backside hood 50 is located generally beneathbackside diverter 24. Backside hood 50 is in fluid communication withbackside ductwork 52. Backside ductwork 52 is in fluid communicationwith exhaust fan (not shown) and filtering facility (not shown). As canbe seen in FIGS. 1 and 2, backside hood 50, in an example embodiment, islocated generally beneath backside diverter 24. Backside hood 50includes backside intake 56. Backside intake 56 is located generally atthe bottom of backside hood 50. In the example embodiment depicted inFIG. 1, backside intake 56 extends over a portion of grizzly 22.

Referring particular to FIG. 2, backside hood 50 may include a number ofbackside sub-hoods 58. In an example embodiment depicted in FIG. 2, sixbackside sub-hoods 58 are included. In FIG. 2, backside sub-hoods 58 areeach located in bays 60. Generally, each backside sub-hood 58 includesstraight portion 62, tapered portion 64, transition portion 66 andattached exhaust duct 68. In an example embodiment, straight portion 62has generally parallel sides when viewed from above, tapered portion 64tapers from straight portion 62 to transition portion 66. Both straightportion 62 and tapered portion 64 may tapered somewhat when viewed fromthe side. Transition portion 66 transitions in shape from a generallyrectangular cross section of straight portion 62 and tapered portion 64to the generally circular cross section of exhaust duct 68.

Each backside sub-hood 58 may include secondary intake 70. Secondaryintake 70 comprises a fluid communication that passes through backsidediverter 24 and into backside sub-hood 58. As depicted in FIG. 2, in anexample embodiment, secondary intake 70 may be located approximately atthe juncture between tapered portion 64 and transition portion 66,however, this should not be considered limiting.

Referring particularly to FIGS. 3, 4 and 6, secondary intake 70 allowsfluid communication of backside sub-hood 58 with the space above,backside diverter 24. Secondary intake 70 may be generally slit shapedas depicted herein. However, this should not be considered limiting assecondary intake 70 may include other shapes including circular, squareor rectangular. The secondary intake 70, in an example embodiment may,include a generally horizontal oriented rectangular slit. Secondaryintake 70 may include chamfered edges 72.

Referring to FIGS. 5 and 5A, rotational frame 16 is depicted rotatedapproximately 90°, first baffle 40 and second baffle 42 is in contactwith backside diverter 24. As depicted in FIGS. 5 and 5A, this contactcreates first interbaffle space 74. First inter baffle space 74 isbounded by first baffle 40, second baffle 42, backside diverter 24 andbaffle support 38. Secondary intake 70 is located so that firstinterbaffle space 74 is in fluid communication with backside hood 50,via backside sub-hood 58, when first baffle 40 and second baffle 42 arein contact with backside diverter 24.

Referring to FIGS. 7 and 7A, rotational frame 16 is pictured havingrotated approximately 125°. At this stage in the rotation, first baffle40 has cleared the upper edge of backside diverter 24. Second baffle 42and third baffle 44 are in contact with backside diverter 24. Secondinterbaffle space 76 is thus bounded by second baffle 42, third baffle44, dumpside diverter 26 and baffle support 38. Second interbaffle space76, as depicted, is in fluid communication with backside hood 50 viasecondary intake 70.

Referring to FIGS. 8 and 8A, rotational frame 16 is depicted havingrotated approximately 155°. In this orientation, both first baffle 40and second baffle 42 have cleared the upper edge of backside diverter24. Third baffle 44 remains in contact with backside diverter 24. Atthis point of the rotation second interbaffle space 76 is opened to theair near upper portion 12 of car dumping facility 10.

In an example embodiment of the invention, secondary intake 70 islocated relative to backside hood 50 at a location where pressure withinbackside hood 50 remains neutral or negative relative to the pressurewithin pit 20 when a load of granular material is being dumped from railcar 30 into pit 20. The dumping of granular material from rail car 30brings along with it a rush of air that is carried along by the granularmaterial as it departs rail car 30 and is carried by gravity into pit20. This rush of air creates increased pressure in pit 20. Negativepressure is generally maintained within backside hood 50 and backsideductwork 52 because of the action of exhaust fans (not shown) in thefiltering facility (not shown). As the rush of air that accompanies thegranular material being dumped enters pit 20, pressure within pit 20rises and pressure within the lower portion of backside hood 50 rises aswell. There is a location within backside hood 50 and/or backsideductwork 52 at which pressure remains neutral or negative because of theaction of exhaust fans (not shown).

In an example embodiment of the invention, secondary intakes 70 arelocated such that they are adjacent to the portion of backside hood 50at which air pressure remains neutral or negative relative to theelevated pressure in pit 20 caused by the dumping of granular material.Additionally, secondary intake 70 being located at this location allowssecondary intake 70 to facilitate the evacuation of dust laden air fromfirst interbaffle space 74 when secondary intake 70 is in fluidcommunication with first interbaffle space 74 and from secondaryinterbaffle space 76 when secondary intake 70 is in fluid communicationwith second interbaffle space 76.

Referring to FIGS. 5, 5A, 7, 7A and 8-8A, in operation, rail car 30 isindexed within rotational frame 16 as depicted in FIG. 1. Rail car 30 issecured to rotational frame 16 and rotational frame 16 begins rotatingas depicted in FIG. 5. As rotational frame 16 and rail car 30 rotate,granular material (not shown) within rail car 30 begins dump into pit20. As rotational frame 16 continues to rotate as depicted in FIGS. 5,5A, 7, 7A, and 8, 8A, granular material (not shown) continues to pourfrom rail car 30 into pit 20.

As granular material (not shown) pours from rail car 30 into pit 20, thepressure within pit 20 rises because of the on rush of air carried alongwith the granular material (not shown). Referring to FIGS. 5 and 5A,when rotational frame 16 reaches a certain point in rotation, fluidcommunication is established between secondary intake 70 and firstinterbaffle space 74. At this point, first interbaffle space 74 may befilled with dust laden air from the dumping of granular material fromrail car 30 in the pit 20. Dust laden air is then withdrawn frominterbaffle space 74 into backside hood 50 because of the relativelylower pressure in backside hood 50.

As rotation of rotational frame 16 continues, as depicted in FIGS. 7 and7A, second interbaffle space 76 establishes fluid communication withsecondary intake 70. Because secondary intake 70 is located relative tobackside hood 50, where internal pressure in backside hood 50 remainsneutral or negative relative to pit 20 as second interbaffle space 76,dust laden air is withdrawn from second interbaffle space 76. Becausedust laden air has been withdrawn from first interbaffle space 74, nopuff of dust laden air is released from first interbaffle space 74 whenit reaches the position depicted in FIGS. 7 and 7A. Further no puff ofdust laden air escapes from second interbaffle space 76 when it reachesthe position depicted in FIGS. 8 and 8A. Thus, the present inventionprevents or reduces the release of environmental contaminants from pit20 in car dumper facility 10.

Rotational frame 16 carrying empty rail car 30 then can be returned tothe upright position as depicted in FIG. 1 and removed from the cardumper facility 10 so that another rail car 30 that is loaded may beindexed for dumping.

The invention may be embodied in other specific forms without departingfrom the spirit of the essential attributes thereof, therefore, theillustrated embodiments should be considered in all respects asillustrative and not restrictive, reference being made to the appendedclaims rather than to the forgoing description to indicate the scope ofthe invention.

Various embodiments of systems, devices, and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the claimed inventions. It should beappreciated, moreover, that the various features of the embodiments thathave been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions,shapes, configurations and locations, etc. have been described for usewith disclosed embodiments, others besides those disclosed may beutilized without exceeding the scope of the claimed inventions.

Persons of ordinary skill in the relevant arts will recognize that thesubject matter hereof may comprise fewer features than illustrated inany individual embodiment described above. The embodiments describedherein are not meant to be an exhaustive presentation of the ways inwhich the various features of the subject matter hereof may be combined.Accordingly, the embodiments are not mutually exclusive combinations offeatures; rather, the various embodiments can comprise a combination ofdifferent individual features selected from different individualembodiments, as understood by persons of ordinary skill in the art.Moreover, elements described with respect to one embodiment can beimplemented in other embodiments even when not described in suchembodiments unless otherwise noted.

Although a dependent claim may refer in the claims to a specificcombination with one or more other claims, other embodiments can alsoinclude a combination of the dependent claim with the subject matter ofeach other dependent claim or a combination of one or more features withother dependent or independent claims. Such combinations are proposedherein unless it is stated that a specific combination is not intended.

Any incorporation by reference of documents above is limited such thatno subject matter is incorporated that is contrary to the explicitdisclosure herein. Any incorporation by reference of documents above isfurther limited such that no claims included in the documents areincorporated by reference herein. Any incorporation by reference ofdocuments above is yet further limited such that any definitionsprovided in the documents are not incorporated by reference hereinunless expressly included herein.

For purposes of interpreting the claims, it is expressly intended thatthe provisions of 35 U.S.C. § 112(f) are not to be invoked unless thespecific terms “means for” or “step for” are recited in a claim.

The invention claimed is:
 1. A method of installing a dust controlapparatus for use in an apparatus for rotary dumping of rail cars, themethod, comprising: creating a first interbaffle space and a secondinterbaffle space underlying a rotational frame that rotates along withrailcars during rotary dumping, the first interbaffle space and thesecond interbaffle space being partially bounded by three baffles;installing a baffle support and the three baffles to be supported by arotational frame that rotates along with the rail cars during the rotarydumping; installing a diverter having a concave curved upper surface,overlying a backside hood; installing the backside hood including aprimary air intake, opening into a pit into which the rail cars aredumped and installing a first secondary air intake, opening into thefirst interbaffle space during at least a first portion of the rotarydumping and opening into the second of the interbaffle spaces during atleast a second portion of the rotary dumping depending upon a rotationalposition of the baffle support; and coupling the primary air intake influid communication with the backside hood and facilitating extractionof dust laden air from the pit and coupling the the first secondary airintake in fluid communication with the backside hood and therebyfacilitating extraction of dust laden air from the first interbafflespace or the second interbaffle space.
 2. The method as claimed in claim1, further comprising locating the first secondary air intake a firstdistance from a lower edge of the backside diverter approximately equalto the first interbaffle space.
 3. The method as claimed in claim 1,further comprising constructing the backside hood to have at least twosubhoods each having a tapered portion and a transition portion andinstalling at least a second secondary air intake, and locating each ofthe first secondary air intake and the second secondary air intakesproximate a junction between the tapered portion and the transitionportion.
 4. The method as claimed in claim 1, further comprising formingthe first secondary air intake to be slit-shaped having a long axis andorienting the long axis of the slit-shaped first secondary air intakehorizontally.
 5. The method as claimed in claim 1, forming the firstsecondary air intake to have chamfered edges.
 6. The method as claimedin claim 1, further comprising installing a dumpside diverter locatedgenerally on a dump side of the pit.
 7. A backside hood for use in anapparatus for rotary dumping of rail cars, comprising: a structuredefining a primary air intake opening and a first secondary intakeopening such that the first secondary intake opening fluidlycommunicates between an interior of the backside hood and a first spaceor a second space during at least a part of the rotary dumping anddepending upon a rotational position; a diverter having a concave curvedupper surface, overlying the backside hood; and the first secondaryintake opening passing through the concave curved upper surface andcommunicating between the interior of the back side hood and a spaceabove the concave curved upper surface and being located such that thefirst secondary air intake opening is in fluid communication with thefirst space during a first portion of the rotary dumping and in fluidcommunication with the second space during a second portion of therotary dumping.
 8. The backside hood as claimed in claim 7, furthercomprising a tapered portion and a transition portion and wherein thefirst secondary air intake opening is located proximate a junctionbetween the tapered portion and the transition portion.
 9. The backsidehood as claimed in claim 7, further comprising ductwork in fluidcommunication with an exhaust fan.
 10. The backside hood as claimed inclaim 7, further comprising at least two subhoods each having a taperedportion and a transition portion and further locating the firstsecondary air intake opening proximate a junction between the taperedportion and the transition portion.
 11. The backside hood as claimed inclaim 7, further wherein the first secondary air intake opening isslit-shaped having a long axis oriented horizontally.
 12. The backsidehood as claimed in claim 7, wherein the first secondary air intakeopening comprises chamfered edges.
 13. The backside hood as claimed inclaim 7, wherein the backside hood is located in a pit into which therail cars are dumped.